Effect of hypothyroxinemia on the emotion in developing rats / 国际儿科学杂志

ABSTRACT

Objective To investigate the effect of hypothyroxinemia on emotion and hippocampus neurons in developing rats.Methods Sixty-nine healthy postnatal day (PD) 1 rats were randomly divided into control group (n =36) and experimental group (n =33).On PD1,experimental group was bilaterally thyroidectomized to establish hypothyroxinemia model,the control group was only given thyroid exposure operation without thyroid resection.On PD10,21,40,serum triiodothyronine (T3),thyroxine (T4),thyrotropicstimulating hormone (TSH) were detected by radioimmunoassay.Tail suspension test,forced swimming test,the elevated-plus maze and open field were respectively employed to detect the anxiety/depression like behavior on PD30,31,32,33.Nisslg staining was used to determine the survival of neurons at PD10,21,40 in hippocampus CA1,CA3,DG regions.Results Serum T4 levels on PD10,21,40 in experimental group decreased significantly as compared with control group (P ＜0.01),while there was no significant difference in serum T3 or TSH level (P ＞ 0.05).In the tail suspension test,immobility time of experimental group [(197.00 ± 19.50) s] was longer than control group [(158.33 ± 32.90) s,P ＜0.05].In the forced swimming test,immobility time of experimental group[(92.11 ± 35.24) s] was longer than control group [(62.00 ± 23.73) s,P ＜ 0.05].In the elevated plus-maze test,total number of arm entries and closed arm entries in experimental group were increased as compared with control group(P ＜ 0.05),percentage of closed arm/total time of experimental group was decreased as compared with control group(P ＜ 0.05).In the open field,there was no obvious difference between the two groups(P ＞ 0.05).On PD10,21,40,the amount of neurons in DG region of experimental group were less than control group(P ＜0.05),while there was no significant difference in CA1 or CA3 on PD10,21,40(P ＞0.05).Contusions Hypothyroxinemia can cause depression,hyperactivity and hippocampus neuron damage of developing rats.